diff --git a/stage0/astgen.c b/stage0/astgen.c
index 84f39c701b..91ce859a3b 100644
--- a/stage0/astgen.c
+++ b/stage0/astgen.c
@@ -111,7 +111,9 @@ typedef struct {
     bool fn_var_args; // AstGen.zig:46
 } AstGenCtx;
 
-#define SET_ERROR(ag) (ag)->has_compile_errors = true
+#define SET_ERROR(ag) do { \
+    (ag)->has_compile_errors = true; \
+} while(0)
 
 // Set fn_block pointer on AstGenCtx. The caller is responsible for saving
 // and restoring the previous value before the pointed-to GenZir goes out
@@ -2924,9 +2926,12 @@ static uint32_t comptimeExpr(
     case AST_NODE_MULTILINE_STRING_LITERAL:
     case AST_NODE_ENUM_LITERAL:
     case AST_NODE_ERROR_VALUE:
+    case AST_NODE_ANYFRAME_LITERAL:
+    case AST_NODE_ERROR_SET_DECL:
     // Type expressions that force comptime eval of sub-expressions
     // (AstGen.zig:2017-2042).
     case AST_NODE_ERROR_UNION:
+    case AST_NODE_ANYFRAME_TYPE:
     case AST_NODE_MERGE_ERROR_SETS:
     case AST_NODE_OPTIONAL_TYPE:
     case AST_NODE_PTR_TYPE_ALIGNED:
@@ -7544,6 +7549,19 @@ static uint32_t exprRl(GenZir* gz, Scope* scope, ResultLoc rl, uint32_t node) {
         return rvalue(gz, rl,
             addStrTok(gz, ZIR_INST_ERROR_VALUE, str, error_token), node);
     }
+    // anyframe_literal (AstGen.zig:1008-1011).
+    case AST_NODE_ANYFRAME_LITERAL: {
+        uint32_t result = addUnNode(gz, ZIR_INST_ANYFRAME_TYPE,
+            ZIR_REF_VOID_TYPE, node);
+        return rvalue(gz, rl, result, node);
+    }
+    // anyframe_type (AstGen.zig:1012-1016).
+    case AST_NODE_ANYFRAME_TYPE: {
+        uint32_t return_type = typeExpr(gz, scope, nd.rhs);
+        uint32_t result = addUnNode(gz, ZIR_INST_ANYFRAME_TYPE,
+            return_type, node);
+        return rvalue(gz, rl, result, node);
+    }
     // error_set_decl (AstGen.zig:5905-5955).
     case AST_NODE_ERROR_SET_DECL: {
         AstData esd = ag->tree->nodes.datas[node];
@@ -9455,6 +9473,7 @@ static uint32_t switchExprErrUnion(GenZir* parent_gz, Scope* scope,
         memset(&err_scope, 0, sizeof(err_scope));
         memset(&capture_scope_val, 0, sizeof(capture_scope_val));
 
+        bool err_scope_used = false;
         err_scope = (ScopeLocalVal) {
             .base = { .tag = SCOPE_LOCAL_VAL },
             .parent = &case_scope.base,
@@ -9462,6 +9481,7 @@ static uint32_t switchExprErrUnion(GenZir* parent_gz, Scope* scope,
             .inst = err_inst + ZIR_REF_START_INDEX,
             .token_src = error_payload,
             .name = err_name,
+            .is_used_or_discarded = &err_scope_used,
         };
 
         Scope* sub_scope = &err_scope.base;
@@ -9556,26 +9576,9 @@ static uint32_t switchExprErrUnion(GenZir* parent_gz, Scope* scope,
                 block_scope.break_result_info, body_node);
 
             // Track err capture usage (AstGen.zig:7489-7494).
-            // The upstream tracks scope usage via used/discarded fields.
-            // We approximate: err capture is "used" if the err_scope was
-            // found during identifier lookup (i.e., the err name was
-            // referenced in the body). Since we don't track scope usage
-            // in C, we check if any instruction in the body references
-            // the err_inst placeholder.
-            bool uses_err = false;
-            {
-                uint32_t rbl = gzInstructionsLen(&case_scope);
-                const uint32_t* rbody = gzInstructionsSlice(&case_scope);
-                for (uint32_t bi = 0; bi < rbl; bi++) {
-                    uint32_t inst = rbody[bi];
-                    // Check if any instruction data references err_inst.
-                    ZirInstData d = ag->inst_datas[inst];
-                    if (d.un_node.operand == err_inst + ZIR_REF_START_INDEX) {
-                        uses_err = true;
-                        break;
-                    }
-                }
-            }
+            // Uses scope tracking: is_used_or_discarded on err_scope is set
+            // to true during identifier lookup when the err name is resolved.
+            bool uses_err = err_scope_used;
             if (uses_err) {
                 addDbgVar(&case_scope, ZIR_INST_DBG_VAR_VAL, err_name,
                     err_inst + ZIR_REF_START_INDEX);